I haven't seen anyone else say this on this forum but I'll start the argument:

I have only spent some time on G3/3.5 & G4. I have heard RealFlight said there are no physics differences but I would argue that point. I think some things in G4 are too easy such as; hovering planes, harriers, and flying helis.

If you want to be more realistic I would suggest the G3.5 over the G4. The G4 has more options and the addition of water and float planes is fun for a while.

Fire away